The present invention relates to the field of power over Ethernet, and more particularly to an interchangeable power over Ethernet module having a plurality of configurations and a single unified pin out.
The growth of local and wide area networks based on Ethernet technology has been an important driver for cabling offices and homes with structured cabling systems having multiple twisted wire pairs. The ubiquitous local area network, and the equipment which operates thereon, has led to a situation where there is often a need to attach a network operated device for which power is to be advantageously supplied by the network over the network wiring. Supplying power over the network wiring has many advantages including, but not limited to; reduced cost of installation; centralized power and power back-up; and centralized security and management.
Several patents addressed to this issue exist including: U.S. Pat. No. 6,473,608 issued to Lehr et al., whose contents are incorporated herein by reference and U.S. Pat. No. 6,643,566 issued to Lehr et al., whose contents are incorporated herein by reference. Furthermore a standard addressed to the issue of powering remote devices over an Ethernet based network has been published as IEEE 802.3af-2003, whose contents are incorporated herein by reference.
The implementation of an integrated switch supplying power over Ethernet functionality into a switch is advantageously accomplished by the use of a plugable module. Such a plugable module allows for implementing power over Ethernet functionality into a switch as required, and further allows for upgrades over time. Plugable modules are typically supplied in any of a number of industry standard pin layouts, so as to be compatible with low cost high volume sockets. Examples of such standard pin layouts are the Dual in-line Memory Module (DIMM) and the Single in-line Memory Module (SIMM) as specified by the JEDEC Solid State Technology Association of Arlington, Va.
An Ethernet switch is typically designed to support a plurality of ports, and power over Ethernet functionality may be supplied for some or all of the supported plurality of ports. For example, in a 48 port Ethernet switch or hub, only 12 or alternatively 24 of the ports may be initially provided with Power over Ethernet functionality. A separate module is then later added to provide Power over Ethernet functionality to additional ports.
In such a configuration, the initially provided module must supply 100% of the required functionality for the initial ports for which Power over Ethernet functionality is being supported, including any required supervisory control circuitry. The later added module may be provided without supervisory control circuitry, receiving its instructions from the supervisory control circuitry of the initially provided module. Preferably, different module types are available, with an enhanced module having added functionality not available in the basic module.
The term supervisory control circuitry, is meant to include any circuitry which provides supervisory control functionality for a plurality of power over Ethernet managing circuits. Such supervisory control circuitry may be included as part of one or more power over Ethernet managing circuits, or as a separate controller or microcontroller.
Field installation of such modules is preferably designed to be location independent, and to be interchangeable, such that a user can change between using basic modules and enhanced modules by simply unplugging the undesired modules and plugging in the desired modules. Furthermore, preferably the modules are interchangeable as to location, such that the location of the initially provided module and the later added module is not critical. This allows for field swapping of the modules and fewer errors caused by improper installation.
What is needed therefore, and is not provided by the prior art, is an interchangeable power over Ethernet module having a plurality of configurations.